Welding-controller.



T. D. MONTGOMERY. WELDING CONTROLL E R.

APPLICATION FILED APR-17,1916. 1,278,368. PatentedSept. 10, 1918.

GoME'RY, acitizen of the United States,.re-

U ITE WISCONSIN.

sf'rarns FATE "THEODORE? n. MONTGOMERY, OF EAST ORANGE, NEW JERSEY, assieivon TO THE CUTLER-HAMMER MFG. 00., or MILWAUKEE, WISCONSIN, A CORPORATION E WELDING-CONTROLLER.

To all wk'om it may concern:

- Be it knownthat LTHEoDonE D. MONT- siding at East Orange, in the county of Essex and State of New Jersey, haveinvented new and useful Improvements in I elding-Contro-llers, of which the following is 'a specification.

. This invention relates to welding controllers.

-' The'electric arc used in arc welding is generally 'obtained by completing an electric circuit by means of welding electrodes and subsequently separating the electrodes to draw an arc. Various controllers have been 'devised for limiting the flow of current through the electrodes. It has been proposed to connect a resistance in the welding circuit to limit the flow of current and provide means to exclude the resistancewhen the weldingcurrenthas decreased to a predeof time and consequently. must be made 40 termined value to thereby increase the voltage across the arc to produce an arc of I suflicient'length and volume for welding purposes.

A controller employing an electromagnetic switch for excluding the resistance is described in a copending application of Tower, and van Nest, Serial'No. 13,608,

'March- 11, 1915. The electromagnetic switch in said controller is adapted to remain open when the initialcurrent through its operating windings is high and to close when the current decreases to a predetermined value. The windings of the switch remain in whole or in part in the welding circuit during the welding operations. They are thus subjected I to heavy current for a considerable length heavy to prevent heating. This increases the size and adds to the expense of the controller.

The present invention relates morepar- -ticularl to an improvement in the type of control or described in said. application in which means is. provided for holding the ing means for holding' 'its automatic switch j Specification" of Letters Patent.

decreases.

Patented Sept. 10, 1918.

. Application filed April 17,1916. Serial No. 91,637.

closed independently of the switch operating windings. Y

The accompanying drawings illustrate an embodiment ofthe invention. -Figure 1 isa diagrammatic view of a welding controller embodying the invention.

Fig. 2 is a side view of the controller mounted on a switch board.

' Fig. 3 is a front elevation of the com illustrated'in Fig. 1 will first be described.-

55. 'Other objects-and advantages of the in'- .vention will hereinafter appear.

Connected between the supply mains 1 and.

2 are the electrodes 3 and 4. The electrode 3 constitutes the object uponwhich.

the welding operation is to be performed. The electrode 4 is movable so that it may trode 3 to complete the circuit and to be thereafter drawn away to strike an arc.

The heat of the arc is used to weld a portion of the object 3. It is, of course, understood that the controller can be used with other forms of electrodes used to draw an electric arc.

' The electrodes are normally connected across the mainsin series witha starting resistance 5 and a steadying resistance I 6. The clrcuit including the resistance 5 may be be brought into engagement with the eleccalled for convenience the auxiliary or startflow of current when the arc is started.

The steadying resistance 6 which is of relatively. small value is used to steady the arc and to dampen abnormal fluctuations in been excluded.

As the electrodes are separated and the arc- 1s drawn, the reslstance of-the arc increases and the fiow of current. consequently The resistance of the are added to that of resistancesoand 6 will generally not permit suflicient current to flow to produce an arc of-the proper-volume for welding purposes. It is therefore importantthat in series with the electrodes and the start- .ing resistance in the starting circuit. The

switch operating means is therefore respon siye to the current in the auxiliary or start ing circuit. In order to prevent the switch closingwhen the circuit is first completed by the electrodes, the switch is constructed so that when the initial current through its windings is high it remains open but when the current decreases to a predetermined value the switch closes. During the welding operation a comparatively heavy current flows throughthe op open position.

crating circuit. If the si'vitch windings 9 and 10 were to remain in circuit they would be subjected to heavy current and would have to be built to accommodate it. It the windings be deenergized after the switch closes, the switch will automatically open since it is normally biased to In order to prevent the windings 9 and 10 being subjected to heavy currents and at the same time keep the switch closed, an additional winding 11 is provided which is connected in the circuit in shunt to the resistance The winding 11 comprises a few turns of 7 heavy copper strip of suflicient size to easily accommodate the welding current without heating. Accordingly when the switch closes the operating windings 9 and 10 are shunted and the winding .11 is energized to hold the switch closed. The welding current thereafter flows through the winding 11 and keeps the switch closed until the circuit is interrupted. Wlien the are between the electrodes-is brokenall the windings are deenergized and the switch automatically moves to open position. The controller thus returns to its initial position ready for another operation.

.The construction of the switch 7 will now be described. The switch is shown in de tail on the controller switch board in Figs. 2 and 3. I

The switch has two operating windings 9 and 10 connected in series and magnetically independent. Winding 9 acts to close the switch and the winding 10 to hold. it open. Mounted between the windings is a movable member'12 carrying acontact 18 which is adapted to engage a stationary contact 1st. The upper part of the movable member constitutes an armature for the core of wind- 'ing'9. The lower end of the movable niem 1,2. races ber carries an armature 15 adapted to be attracted by the core of winding 10. The

pull'cliaracteristicsl The pull of winding-9 for closing the switch lags behind the cur- Y rent whereas the pull of the winding 10 for holding the switch open rises very quickly with an increase in current. Consequently when an initially high current is passed through the windings, the pull of the holding winding 10 increases more rapidly than that of the closing winding 9 and the switch remains open. As the current decreases the pull of the holding winding '10 decreases more rapidly than that of the closing Winding 9 until a point is reached where the closing winding predominates over the holdlug winding and closes the switch.

The winding 11 for holding the switch closed after it has been operated is mount-' ed on the core of winding 9 and connected to the stationary contact 14 and to the terminal 16, the latter being also connected to one end of th coil 9.

The switch is mounted on the controller board 17 together with the resistances 5 and S which are in the form of suitable rheostats controlled by adjustable handles 18 and 19. The controller elements may thus be grouped and connected together on a compact panel which may be easily tramsported. Thecontroller can be quickly put into operation by merely connecting it to the supply line and to the electrodes.

It is to be understood that the structure shown is for the purpose of illustration only and that other structures may be devised which embodv the invention and come within the spirit and scope of the appended claims. 9

What I claim is 1'. An arc welding controller provided with a resistance adapted to be connected in the circuit of the arc, a switch for controlling said resistance, said switch having -a'closing and :1V holding winding in series with the resistance and arranged so that i when the current through the resistance is initially high the switch is held open. and when'the current decreases to a predetermined value the switch is closed, and an additional winding for the switch to keep it closed independently of the closing and holding windings.

2. An electric welding system comprising a-sourc'o of current supply, an auxiliary circuit for starting the welding arc, a main operating circuit adapted to'be connected to the source of current supply, means directly magnetic operating means responsiveto the responsive to the current in the auxiliary circuit for closing the main circuit when the current in the auxiliary circuit reaches a predetermined value, and means in the main circuit -for maintaining said first-named means in circuit closing vposition.

3. An electric Welding system comprising a source of current supply, an auxiliary circuit for starting the welding arc, a main operating circuit adapted to be connected to the source of current supply, a switch having' electromagnetic operating means re- .-spons1ve to the current, in the auxiliary, c1r- 'cuit for closing the main circuit when the current in the] auxillary circuit reaches a predetermined value and electromagnetic -means in the main circuit for keeping the" switch closed independent of the operating means.

4. A Welding system comprising a starting circuit for the welding are adapted to be connected to a source of hurrent supply, means in said .circuit'for'limiting the'current flow, a normally open operating circuit in shunt to said current limiting means, a switch in' said shunt circuithaving electroconnected to a source of current supply, current hmlting means 1n said c1rcu1t, a normally open operating circuit in shunt to said current limiting means, a switch for control ling the shunt circuit, said switch having a closing and a holding winding inseriesin thestarting circuit to hold the switch open when the initial current decreases to Cr-pre determined Value,-and an additional winding for said switch responsive to the current in theshunt circuit for holding the switch closed independently of the other windings.

G. A welding system'comprising a at v I ing circuit for the welding are adapted to be" connected to a source of current supply, current limiting means in said circuit, a nor-- mal-ly open operating circuit in shunt to said.

- current limiting means, ,a'lockout switch for controlling the shunt circuit, said switch havin its WHIdIH S res onsive to the circuit I l a b n u in the start ng c1rcuit-so that the shunt fill? cuit remains open when the initial current 1n the starting circult is high and ls'closed.

when the current decreases to a predetcrmined value, and electromagnetic means for said lockout switch responsive to the current in the shunt operating circuit for maintainmg the SWltCh'ClOSGCl independently of the operative windings.

7. A welding system comprising a-starting circuit for the welding are adapted to be connected to a source of current supply,

current limiting means in said circuit, a

magnetic switch having operating means responsive to the current in saidstarting circuit, an operating circuit adapted to be closed by said switch to exclude said current limiting means and the operating means of the switch, and means responsive to the current in the operating circuit for maintaining the switch closed after its operating means has been. excluded Inwitnessnwhereof I have hereunto sub scribed mynanie inthe presence of two witnesses.

11D. MONTGrOMERY.-

' Witnesses ALFRED J. 'KUTGHERA, ,LAURA E. SMITH.

copies of this patent may be obtained for ave cents each, liy'afiiressing the .Gommiasi oner ct Eateute,

' weeningtea. It, 3. 

